Vim: disable word wrapping for specific lines - vim

Question

I am using :set textwidth=80 to make the Vim editor do hard wrapping automatically. However, sometimes for certain lines within a file (e.g. tables in LaTeX), I do not want Vim to do any hard wrapping automatically. Is there a way to mark certain lines to disable hard wrapping in Vim? Or automatically :set textwidth=0 just for specified lines?

Answer 1

There's nothing out-of-the-box, but you can build a solution with an :autocmd <buffer> on the CursorMoved,CursorMovedI events. On each move of the cursor, you have to check whether you're currently in one of those "certain lines", and modify the local 'textwidth' option accordingly:
autocmd CursorMoved,CursorMovedI <buffer> if IsSpecialLine() | setlocal textwidth=0 | else | setlocal textwidth=80 | endif
Put this into ~/.vim/after/ftplugin/tex.vim. (This requires that you have :filetype plugin on; use of the after directory allows you to override any default filetype settings done by $VIMRUNTIME/ftplugin/tex.vim.) Alternatively, you could define an :autocmd FileType tex autocmd ... directly in your ~/.vimrc, but this tends to become unwieldy once you have many customizations.
For the IsSpecialLine() function, you probably need to match a regular expression on the current line (getline('.') =~# "..."). If you can identify the "certain lines" through syntax highlighting, my OnSyntaxChange plugin can do all the work for you.

Answer 2

I've tried Ingo Karkat answer. Although it does work very well and does what the OP asks, I find it distracting (if I have long tables with row hundreds of characters long, there are a lot of shifts up and down when passing over tables) and can slow down a lot vim on big files (the textwidth and wrap are changed for the whole file, so running the autocmd for every cursor movement can be costly).
So I propose a static solution based on the idea that hopefully you have to modify a table as few times as possible. I've added the following to my ftplugin/tex.vim file:
" By default the text is
let s:textwidth = 90
let &l:textwidth=s:textwidth
" Toggle between "textwidth and wrap" and "textwidth=0 and nowrap".
" When editing a table, can be useful to have all the '&' aligned (using e.g.
" ':Tabularize /&') but without line brakes and wraps. Besides it's very
" annoying when line brakes "happen" while editing.
" As hopefully tables must be edited only from time to time, one can toggle
" wrap and textwidth by hand.
function! ToggleTwWrap() "{{{
" if textwidth and wrap is used, then disable them
if &textwidth > 0
let &l:textwidth=0
setlocal nowrap
else " otherwise re-enable them
let &l:textwidth=s:textwidth
setlocal wrap
endif
endfunction
So now if I want to edit manually a table I simply do
:call ToggleTwWrap()
to disable wrapping and textwidth and then again when I'm done with the table.
And of course you can create a command or a map

Answer 3

You can certainly set it for specific file types, but I don't think you can change those settings (or any, really) for individual lines.

Answer 4

Ingo Karat's answer works but setting textwidth on every single cursor move is too slow. This adapted version will only call setlocal textwidth= if the text width is actually going to change. This speeds things up considerably:
autocmd CursorMoved,CursorMovedI <buffer> if IsSpecialLine() | if &textwidth != 0 | setlocal textwidth=0 | endif | else | if &textwidth != 80 | setlocal textwidth=80 | endif | endif